The present invention relates generally to automated loading of fuel assemblies for nuclear reactors. It comprises a valve for preventing contamination spread along a length of cladding during and after loading of the cladding with nuclear fuel.
This disclosure relates to the assembly of nuclear fuel assemblies, particularly for use in fast breeder reactors. The present state of the art involves fabrication of fuel assemblies by manual manipulation or by mechanical processes incapable of limiting spread of radioactive contamination to adjoining components and equipment. In such configurations, the fabrication steps are time consuming and create significant radiation contamination control problems.
To achieve flexibility of process steps, radiation contamination control, and efficient fabrication in an apparatus having production capability, the present invention has been directed toward development of a self-contained automated loading system.
A major concern when loading fuel assemblies, particularly by automated equipment, is to assure that reactive particles are not carried from the loading area when the fuel assembly is removed. This requires use of an effective seal about each cylindrical length of cladding during the time it is being filled. According to this disclosure, the seal doubles as an effective gaseous stripping device to clean contaminants from the cladding exterior as the fuel assembly is subsequently retracted.
U.S. Pat. No. 4,167,959 discloses a glove box loading apparatus for fuel rods in which contamination spread is stated to be controlled by differential pressures between adjacent sealed chambers.
An elongated flexible seal that is inflatable to engage transverse portions of moving fuel rods is shown in U.S. Pat. No. 4,070,240.
U.S. Pat. No. 3,907,123 discloses a flexible iris seal at the opening of a fuel loading apparatus. Inflatable dual seals for this purpose are shown in FIG. 2 of U.S. Pat. No. 4,158,601.
U.S. Pat. No. 3,711,993 relates to an airlock or cylindrical seal for engagement about the periphery of fuel cladding.